One day at a time sounds modest until you try to hold it. The mind wants to check progress hourly, and a day is far too short to show anything at all.
Think of pencil marks on a doorframe. Nobody watches a child grow. You notice it in April when the shorts don't fit, and you look back at a line from last summer that felt permanent when it was drawn.
Growth is measured backward and lived forward. Today will feel like nothing much, and that is the correct feeling. Do the small thing anyway, and let the doorframe keep the record you can't keep yourself.